The water level in Marikina River reached 18 meters above sea level at 4:57 p.m., prompting local officials to raise the third alarm.

This means the local government's disaster response unit will implement forced evacuations of residents along the river.

The river quickly rose Saturday afternoon due to heavy downpour, flooding several areas in the city.

The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) has also raised red rainfall warning over Metro Manila and Rizal province, warning of serious flooding in these areas.

Two weather disturbances outside the country are enhancing southwest monsoon that is causing the inclement weather, PAGASA said.